When X-Plane checks X-Plane.com for updates, it calls the server with an identifier for itself that contains a little bit of information about the host machine it is running on: operating system type and version, whether it is the 64-bit or 32-bit version, and whether it is running as a demo.* (X-Plane does not send any personally identifying information about you, but the server can see your IP address because all servers can see the IP addresses of all incoming network traffic.)
I sometimes get asked by third party developers: what percentage of users are using 64-bit, or what percentage of users are on Mac or Linux. So I wrote a script to analyze the incoming data and break it down by platform, etc. Here are the results. (I have done this kind of analysis before, but this is the first time I wrote a good script to remove possibly confounding results.)
The data set consists of 24,917 unique IP addresses that ran a non-demo, global X-Plane 10.25r1 in the last week of 2013. This excludes users who have the regional version, a demo, don't have their DVD in the drive, are running an old version, or who don't have net connectivity. So that's a big enough sample to get good data, even though it's only a fraction of the total X-Plane 10 copies sold. Here's the platform break-down:
IBM: 65.7% APL: 32.2% LIN: 2.0%
This matches the number we've seen ever since FSX development was halted: growing market share for Windows. (We used to be 60-40 Windows/Mac back in the day). Since X-Plane 10 is selling better than X-Plane 9, I believe that what we are seeing is growth, and the growth is disproportionately among Windows users. The Linux share appears to have shrunk, but it's hard to tell since past data wasn't as carefully analyzed. (The highest percent I have ever seen for Linux was 5%, but from this data I estimate the error bars on old data might be +/- a few percent, so who knows.)
Here's the rate of 64-bit adoption for each OS.
All OSes: 82.0% APL: 85.1% IBM: 80.7% LIN: 72.7%
It doesn't surprise me that OS X has the highest 64-bit adoption - every Mac is running a 64-bit operating system and OS X has the least available address space. What does surprise me is that Linux has the lowest 64-bit adoption rate, since Linux users have had the strongest desire for 64-bit. (This desire is, I think, driven by the difficulty of setting up cross-64/32-bit operation on modern distributions.)
Operating System Breakdown
We don't have a break-down of Linux distros or Kernels - the Linux version of the sim doesn't report that, but we do have operating system versions for Windows and Mac. On Windows the _32 and _64 bit suffixes tell whether the user is running the 32 or 64 bit "edition" of the OS.
The numbers include the 64-bit adoption rate for that particular OS; naturally the 64-bit adoption rate on the 32-bit editions of Windows is 0% because those OSes can't run 64-bit X-Plane. Fortunately 64-bit editions of Windows are becoming the norm - of the users running Windows 8, over 98% have the 64-bit edition. On OS X, every version of the OS is 64-bit capable.
Windows: 5.1_32: 1.8% (64-bit: 0.0%) 5.1_64: 0.2% (64-bit: 0.0%) 5.2_64: 0.1% (64-bit: 100.0%) 6.0_32: 0.9% (64-bit: 0.0%) 6.0_64: 0.8% (64-bit: 77.8%) 6.1_32: 4.1% (64-bit: 0.0%) 6.1_64: 66.0% (64-bit: 87.2%) 6.2_32: 0.4% (64-bit: 0.0%) 6.2_64: 25.7% (64-bit: 87.3%) OS X: 10.6.5: 0.1% (64-bit: 42.9%) 10.6.6: 0.0% (64-bit: 100.0%) 10.6.8: 8.8% (64-bit: 78.9%) 10.7.0: 0.1% (64-bit: 28.6%) 10.7.2: 0.1% (64-bit: 100.0%) 10.7.3: 0.0% (64-bit: 100.0%) 10.7.4: 0.1% (64-bit: 81.8%) 10.7.5: 11.3% (64-bit: 78.7%) 10.8.0: 0.0% (64-bit: 100.0%) 10.8.1: 0.0% (64-bit: 0.0%) 10.8.2: 0.4% (64-bit: 88.2%) 10.8.3: 0.3% (64-bit: 88.0%) 10.8.4: 0.7% (64-bit: 84.7%) 10.8.5: 15.0% (64-bit: 82.0%) 10.9.0: 8.0% (64-bit: 84.3%) 10.9.1: 54.7% (64-bit: 88.5%) 10.9.2: 0.2% (64-bit: 100.0%)
Hopefully this is useful for third parties in deciding what operating systems and platforms to support.
* This is a standard practice - the update check runs over HTTP, just like your web browser.